Extinct Animals Were Bigger

Why are there so few large animals today? From fossils, many more extinct animals were huge.

The blue whale is the largest animal alive today, and may be the largest that ever lived (possible exception: see 15 January 2021). But in most cases, the “megafauna” (large animals) of the past were bigger. Cave bears were larger than Alaskan browns. Giant ground sloths were larger than today’s sloths. Beavers grew to almost the size of horses. Saber-tooth cats were larger than today’s lions. Mammoths were larger than elephants. Alligators, sharks, ammonites, penguins, albatross, emus and dragonflies grew bigger than today’s species. And then, on top of all these, the mighty dinosaurs once lifted their heads into the sky.

The Darwinian concept of “fitness” is ambiguous and basically useless since it explains anything, even opposites. Without controversy, though, any animal that can hoist a massive head high up in the air and sustain a bulky body for years has some pretty good design specs. What happened to the Victorian myth of progress that was in full gear in Darwin’s day? Shouldn’t the world champions of the animal kingdom be strutting their stuff in today’s ecosystems?

Giant rhino fossils in China show new species was ‘taller than giraffe’ (BBC News). Look at the artist rendering of this beast that left fossils in China: it looks like a tapir, but towered above the trees. The world record giraffe stood about 18.8 feet by comparison.

The Paraceratherium linxiaense, which lived some 26.5 million years ago, weighed 21 tonnes – the equivalent of four large African elephants. The hornless creature’s head could also reach 23ft (7m) to graze treetops, making it taller than a giraffe.

Record-breaking Aussie dinosaur was as long as a basketball court (Live Science). Photos of kids holding up huge bones accompanies this story about Australotitan cooperensis (“Cooper” for short, Australia’s new record-holding dinosaur.

When alive, Cooper would have stood about 21 feet (6.5 meters) tall at its hip and measured up to 98 feet (30 m) from its snout to the tip of its tail. It likely weighed between 25 and 82 tons (23 and 74 metric tons), or the equivalent of 1,400 red kangaroos, the researchers wrote in a blog post. These metrics mean that the plant-eating Cooper ranks among the top 10 to 15 largest dinosaur species worldwide, the researchers said.

‘Living fossil’ fish may live for up to a century (BBC News). Coelacanths are not extinct, since some are alive today as “living fossils,” and they are not the largest fish of all, but they have another claim to fame. Scientists estimate they can survive for a century.

 

Extinct Sicilian elephant lost 8000 kilograms as it evolved and shrank (New Scientist). This article talks about “island dwarfism,” a story that living on islands makes one smaller. Whether shrinking is a kind of “evolution” that would honor Darwin, fossils make clear that a related species of extinct elephant was bigger than modern forms:

An extinct species of dwarf elephant from Sicily halved in height and shrank by almost 85 per cent in body mass over a period of just 350,000 years after evolving from one of the largest land mammals that ever lived, researchers have found.

Megafauna extinction mystery – size isn’t everything (Flinders University). This press release begins with an artist’s depiction of a monster tree-climbing marsupial as big as a cow.

Palorchestes azeal, sometimes referred to as the ‘marsupial tapir’, was a cow-sized beast, which probably weighed about 500 kg. It was one of the many species of marsupial megafauna that went extinct sometime in the Pleistocene, probably during the last glacial cycle.

The rapid extinction of giant animals including wombat-like creatures as big as cars, birds more than two metres tall, and lizards more than seven metres long that once roamed the Australian continent is a puzzle that has long engaged researchers.

This article finally tries to explain why so many large animals are extinct. Being bigger is too costly; it exposes a species to greater extinction risk, the experts say. Or maybe it was lifespan, reproductive period, access to food or water, or ability to run fast that doomed the heavyweight champs. Then there is the catch-all explanation that can explain any bad situation:

There is a growing consensus that multiple factors were at play, including climate change, the impact of people on the environment, and access to freshwater sources.

If it wasn’t climate change, they can still blame people for some megafauna extinctions: humans who hunted them all down.

And yet many large animals of the past lived for long periods of time in the evolutionary dating scheme. Should not there be more species alive today that are as big or bigger than the record holders of the past?

Biblical creationists can point to post-Flood conditions and Ice Age conditions as major factors contributing to reduction in animal size. It’s a different world now, impoverished in resources compared to the past. At least that explanation fits the evidence better than the all-purpose Stuff Happens Law. Plus, we believe animals are devolving, not evolving. Genetic entropy is reducing the quality of genomes that would be capable of supporting large well-adapted megafauna. Instead of progress, we see regress from the original good creation.

Further reading:

Michael Oard compares secular theories for Pleistocene extinctions with a single Ice Age model at CMI.

Brian Thomas examines the plausibility of human-caused extinctions at ICR.

Marcus Ross asks why Ice Age animals got so big at Answers in Genesis.